The present invention relates generally to devices for producing tension in a line. More particularly, the present invention relates to line tensioner used with adjustable length straps which are useful, for example, in securing a cargo object in place.
The invention is particularly applicable to adjustable length stretchable flexible cargo straps, sometimes known as bungee cords, which are particularly useful for retaining a load in place on, e.g., a vehicle. However, it should be appreciated by those of average skill in the art that the invention has broader applications and may also be adapted for use in many other environments where it is desired to tighten cable, rope, webbing or the like, such as, e.g., tightening a tent rope, a guy wire, a sailing line and so on.
Line tightener and snubbing devices for use with guy ropes and the like permit the effective shortening of a rope to take out the slack and secure it in the tightened position. Prior devices, while they provided for the tightening action and the prevention of slippage, were rather difficult to adjust because of the frictional action of the rope in passing through the device. Also, the known devices of this sort are not simple and inexpensive to manufacture, nor are they easy to use and most of them have several movable parts.
Several types of stretchable flexible cargo straps are known. Light duty cargo straps have been used to hold small articles in place on, e.g. the luggage carriers of bicycles. Medium duty cargo straps have been used to secure luggage, sailboards, skis, lumber, ladders, pipes and the like to cartop carriers or racks on pickup trucks. Heavy duty straps have been employed to secure aircraft to the decks of aircraft carriers. Typically, an attachment means, such as a hook is provided at each end of such flexible cargo straps.
The known stretchable cargo straps have, been the subject of several limitations including, for example, a breakage of the strap. Perhaps the most important limitation of known cargo straps is that it is difficult to maintain the desired amount of tensioning force on the strap. Normally, a stretchable support strap has a given free length or unstretched length. For use, such a strap needs to be stretched to near its maximum "stretchable length" so as to provide an effective tension force to hold a cargo in place. Obviously, the strap should not be stretched past its maximum stretchable length as it will break the strap. Conventionally, one must buy several lengths of straps and experiment to find the right length of strap for a particular job.
In order to vary the stretchable length of a strap, some users pass the hook provided on one end of the cargo strap around a support and then hook it to a central portion of the strap. As this hook slides along the central portion of the cargo strap, the tension in the stretchable cargo strap is diminished and the strap only loosely holds the cargo object to the carrier. This may result in the cargo object being separated from the carrier due to, e.g. wind knocking a surfboard attached to a cartop carrier of a moving vehicle from the vehicle. Obviously, the separation of cargo from its vehicle can cause accidents which should be avoided at all costs. Conventional line tightening devices are not adapted for use with such straps. Even when used with such stretchable flexible cargo straps, they are still subject to the disadvantages mentioned previously.
One improvement on such conventional cargo straps, while it prevents a loosening of the cargo strap, is not infinitely adjustable and is disadvantageous from that standpoint. In addition, this known device necessitates the use of a separate fastening chain located within a tubular stretchable cargo strap. This known cargo strap is not usable with conventional line tightening devices due to the provision of the fastening chain within the strap.
It has therefore been considered desirable to develop a new and improved line tensioner device, for stretchable cargo straps and other types of line, which would overcome the foregoing difficulties and others while providing better and more advantageous overall results.